If we choose to live near convergent plate boundaries, we can build buildings that can resist earthquakes, and we can evacuate areas around volcanoes when they threaten to erupt. Yes, convergent boundaries are dangerous places to live, but with preparation and watchfulness, the danger can be lessened somewhat.
Nitrification, as stated above, is formally a two-step process; in the first step ammonia is oxidized to nitrite, and in the second step nitrite is oxidized to nitrate. Different microbes are responsible for each step in the marine environment.
Even though vegetables also contain nitrates/nitrites, they are rarely exposed to such high heat. Nitrosamines can also form during the acidic conditions in the stomach. Bottom Line: When nitrites and amino acids are present, carcinogenic compounds called nitrosamines can form during high heat cooking.